/*
silverPDF is sponsored by Aleyant Systems (http://www.aleyant.com)

silverPDF is based on PdfSharp (http://www.pdfsharp.net) and iTextSharp (http://itextsharp.sourceforge.net)

Developers: Ai_boy (aka Oleksii Okhrymenko)

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above information and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR SPONSORS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

*/
#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Diagnostics;
using System.Collections;
using System.Reflection;
using System.Text;
using System.IO;
using PdfSharp.Pdf;
using PdfSharp.Pdf.Advanced;
using PdfSharp.Pdf.Content.Objects;

namespace PdfSharp.Pdf.Content
{
  /// <summary>
  /// Provides the functionality to parse PDF content streams.
  /// </summary>
  internal sealed class CParser
  {
    PdfPage page;
    CLexer lexer;

    public CParser(PdfPage page)
    {
      this.page = page;
      PdfContent content = page.Contents.CreateSingleContent();
      byte[] bytes = content.Stream.Value;
      this.lexer = new CLexer(bytes);
    }

    public CParser(byte[] content)
    {
      this.lexer = new CLexer(content);
    }

    public CSymbol Symbol
    {
      get { return this.lexer.Symbol; }
    }

    public CSequence ReadContent()
    {
      CSequence sequence = new CSequence();
      ParseObject(sequence, CSymbol.Eof);

      return sequence;
    }

    /// <summary>
    /// Parses whatever comes until the specified stop symbol is reached.
    /// </summary>
    void ParseObject(CSequence sequence, CSymbol stop)
    {
      CSymbol symbol;
      while ((symbol = ScanNextToken()) != CSymbol.Eof)
      {
        if (symbol == stop)
          return;

        switch (symbol)
        {
          case CSymbol.Comment:
            // ignore comments
            break;

          case CSymbol.Integer:
            CInteger n = new CInteger();
            n.Value = this.lexer.TokenToInteger;
            this.operands.Add(n);
            break;

          case CSymbol.Real:
            CReal r = new CReal();
            r.Value = this.lexer.TokenToReal;
            this.operands.Add(r);
            break;

          case CSymbol.String:
          case CSymbol.HexString:
          case CSymbol.UnicodeString:
          case CSymbol.UnicodeHexString:
            CString s = new CString();
            s.Value = this.lexer.Token;
            this.operands.Add(s);
            break;

          case CSymbol.Name:
            CName name = new CName();
            name.Name = this.lexer.Token;
            this.operands.Add(name);
            break;

          case CSymbol.Operator:
            COperator op = CreateOperator();
            this.operands.Clear();
            sequence.Add(op);
            break;

          case CSymbol.BeginArray:
            CArray array = new CArray();
            Debug.Assert(this.operands.Count == 0, "Array within array...");
            ParseObject(array, CSymbol.EndArray);
            array.Add(this.operands);
            this.operands.Clear();
            this.operands.Add((CObject)array);
            break;

          case CSymbol.EndArray:
            throw new ContentReaderException("Unexpected: ']'");
        }
      }
    }

    COperator CreateOperator()
    {
      string name = this.lexer.Token;
      COperator op = OpCodes.OperatorFromName(name);
#if DEBUG
      if (op.OpCode.Operands != -1 && op.OpCode.Operands != this.operands.Count)
        Debug.Assert(false, "Invalid number of operands.");
#endif
      op.Operands.Add(this.operands);
      return op;
    }

    CSymbol ScanNextToken()
    {
      return this.lexer.ScanNextToken();
    }

    CSymbol ScanNextToken(out string token)
    {
      CSymbol symbol = this.lexer.ScanNextToken();
      token = this.lexer.Token;
      return symbol;
    }

    /// <summary>
    /// Reads the next symbol that must be the specified one.
    /// </summary>
    CSymbol ReadSymbol(CSymbol symbol)
    {
      CSymbol current = this.lexer.ScanNextToken();
      if (symbol != current)
        throw new ContentReaderException(PSSR.UnexpectedToken(this.lexer.Token));
      return current;
    }

    CSequence operands = new CSequence();
  }
}
